title: Phytochrome A regulates the intracellular distribution of phototropin 1-green fluorescent protein in Arabidopsis thaliana.
abstract: It has been known for decades that red light pretreatment has complex effects on subsequent phototropic sensitivity of etiolated seedlings. Here, we demonstrate that brief pulses of red light given 2 h prior to phototropic induction by low fluence rates of blue light prevent the blue light-induced loss of green fluorescent protein-tagged phototropin 1 (PHOT1-GFP) from the plasma membrane of cortical cells of transgenic seedlings of Arabidopsis thaliana expressing PHOT1-GFP in a phot1-5 null mutant background. This red light effect is mediated by phytochrome A and requires approximately 2 h in the dark at room temperature to go to completion. It is fully far red reversible and shows escape from photoreversibility following 30 min of subsequent darkness. Red light-induced inhibition of blue light-inducible changes in the subcellular distribution of PHOT1-GFP is only observed in rapidly elongating regions of the hypocotyl. It is absent in hook tissues and in mature cells below the elongation zone. We hypothesize that red light-induced retention of the PHOT1-GFP on the plasma membrane may account for the red light-induced increase in phototropic sensitivity to low fluence rates of blue light.
authors.affiliation: Department of Biological Sciences, University of Ulsan, Ulsan 680-749, Korea.
authors.forename: In-Seob
authors.initials: IS
authors.lastname: Han
authors.forename: Tong-Seung
authors.initials: TS
authors.lastname: Tseng
authors.forename: William
authors.initials: W
authors.lastname: Eisinger
authors.forename: Winslow R
authors.initials: WR
authors.lastname: Briggs
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000032:analysis / Q000378:metabolism* / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000032:analysis; D008027:Light; D010750:Phosphoproteins / Q000032:analysis / Q000378:metabolism*; D051942:Phytochrome A / Q000502:physiology*; D030821:Plants, Genetically Modified / Q000378:metabolism / Q000528:radiation effects; D017346:Protein Serine-Threonine Kinases; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000032:analysis
chemical_list: D029681:Arabidopsis Proteins; C497973:PHYA protein, Arabidopsis; D010750:Phosphoproteins; D051942:Phytochrome A; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; C103646:NPH1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases